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@@ -1,6 +1,7 @@ $Id: README 26 2009-10-20 18:44:22Z massiot $ Welcome to Multicat! +==================== The multicat package contains a set of tools designed to easily and efficiently manipulate multicast streams in general, and MPEG-2 @@ -29,7 +30,100 @@ signal over several contribution links. The multicat suite of applications is very lightweight and designed to operate in tight environments. Memory and CPU usages are kept to a minimum, -and they feature only one thread of execution. They have no dependancy. +and they feature only one thread of execution. --- -Meuuh 2010-01-07 + +The socket description format +============================= + +For conveniency all tools use the same way of describing a socket in a +program argument: + +<connect address>:<connect port>@<bind address>:<bind port> + +All parts are optional; default port (1234) or wildcard address will then +be used. + +Some examples: + +Reading all streams coming to port 5004: + @:5004 +Reading from a multicast stream on port 5004: + @239.255.0.1:5004 +The same, with source-specific multicast: + 192.168.0.1@239.255.0.1:5004 +Writing to a multicast stream on port 5004: + 239.255.0.1:5004 +The same, but binding to a specific interface: + 239.255.0.1:5004@192.168.0.2 + + +Using Multicat +============== + +Recording a multicast address to a file: + +multicat @239.255.0.1:5004 /tmp/myfile.ts + +This will also create file /tmp/myfile.aux. Playing back the file: + +multicat -p 68 /tmp/myfile.ts 239.255.0.2:5004 + +Adding an RTP header to an existing multicast stream: + +multicat -p 68 -u @239.255.0.1:5004 239.255.0.2:5004 + +The PCR PID is here supposed to be 68. If you don't specify it, the timestamps +will not be RFC-compliant (but will work in most cases). You can use the +get_pcr_pid tool from libdvbpsi to determine it. Otherwise, if you are sure +the stream contains a single program, and only one PID carries a PCR, you can +pass "-p 8192" the disable the PID check. This isn't on by default because +it can produce awful things with multi-program transport streams, and the +world would be a better place if people had to knowingly turn it on. + + +Using IngesTS +============= + +ingests -p 68 /tmp/afile.ts + +This will create file /tmp/afile.aux. 68 is supposed to be the PCR PID. +The same note as above applies to ingesTS. + +Playing the file: + +multicat -p 68 /tmp/afile.ts 239.255.0.2:5004 + + +Using OffseTS +============= + +We want to take the first 60 minutes of a TS file. We must scale it in a +27 MHz clock: +60 * 60 (seconds) * 27000000 (MHz) = 97200000000 + +Find the offset in 1316-blocks: + +offsets /tmp/myfile.aux 97200000000 + +It returns for instance "556896". Then cut the file using dd: + +dd if=/tmp/myfile.ts of=/tmp/mynewfile.ts bs=1316 count=556896 + +Alternatively, if we want to *remove* the first hour: + +dd if=/tmp/myfile.ts of=/tmp/mynewfile.ts bs=1316 skip=556896 + +It can also be done with multicat using the -s and -n options. + + +Using AggregaRTP and DesaggregaRTP +================================== + +Splitting an RTP stream to two streams with different routing policies: + +aggregartp @239.255.0.1:5004 239.1.0.1:5004@192.168.0.1 239.2.0.1:5004@172.16.0.1 + +At the other end, reassembling the two streams into one usable stream: + +desaggregartp 192.168.0.1@239.1.0.1:5004 172.16.0.1@239.2.0.1:5004 239.254.0.1:5004 |